This invention generally relates to a system for identifying a key. More particularly, the present invention relates to a system for identifying the key blank that corresponds to a master key.
There are many circumstances in which a key owner may desire to obtain a copy of a key. For example, the key owner would need to replace a key after the key has undergone significant use and the cuts and notches on the key blade have worn to a point where the key can no longer effectively operate the corresponding lock. A key owner may also desire to create a duplicate key to replace a lost key or simply to obtain an extra key.
To reproduce a key, the type, or style, of key blank used in the master key must be identified from the numerous types of key blanks available in the market. In addition to identifying the appropriate key blank, the cuts, or notches, in the blade of the key may be identified. After the key blank and the key cuts are identified, a key blank corresponding to the master key may be positioned in a clamp and a cutting mechanism employed to reproduce the notches in the blade. The end result of this process is a key that is a reproduction of the original master key.
Each different type, or style, of key blank has different features that uniquely identify the key blank. These features include the head shape, blade length, milling locations and depths, and the number of cut edges (i.e. whether the key is one-sided or two-sided). To identify the appropriate key blank, this information is extracted from the master key and compared to known key blanks. A key blank can be identified when each of the features of the master key is matched to a particular key blank. This comparison process may be performed manually or with an automated identification device. The currently known automated key identification machines extract this information from a master key through a combination of two processes: back lighting and light striping.
In a back lighting process, a light source and a camera are positioned on opposite sides of a master key so that the light from the light source forms a profile of the key for the camera to capture. The captured profile is digitized and the results are analyzed by a processor to extract information about the master key. This back lighting process can reveal information about the head shape, blade length, and whether the key is one-sided or two-sided. However, information about the shape of the key blade surface, such as the location and depth of any grooves or millings, cannot be determined from the profile of the master key. Thus, the back lighting process alone is unable to extract all of the information about the master key needed to identify the key.
The process of light striping will reveal the information that can not be obtained in the back lighting process. In the light striping process, a generally planar beam of light is directed at an angle against the blade of the key. The beam of light is then moved along the length of the key blade, either by moving the key relative to the light stripe and camera or by moving the light stripe and camera relative to the key. The image created by the intersection of the light stripe and the blade surface is captured by a camera. Because of the angle of intersection of the light stripe and the key blade and the differing depths of the key blade surface due to the millings or grooves, the image captured by the camera will be non-linear. This non-linear image may be digitized and analyzed to determine the location and depth of the grooves or millings on the key blade surface.
Key identification machines that identify a key with the light striping and back lighting processes are typically complex machines as they must include the moving parts and multiple lighting sources needed to both back light and light stripe the key blade. In addition, a bright light source, such as a laser, is typically required to generate the light stripe. The use of a laser necessitates that certain safety precautions, such as laser shielding, be included in the light striping device.
In addition, imperfections or dirt on the surface of the key blade can result in glares or shadows under the harsh light of a laser generated light stripe. These glares and shadows are captured as part of the camera image of the light stripe and can reduce the accuracy of the key identification process.
Another problem with known light striping machines is that the master key must be accurately positioned with respect to the light stripe to obtain an accurate identification of the master key. For the light striping process to work, the user must place the key blade perpendicular to the light stripe generator. Any other positioning will result in a distorted non-linear image. If the alignment of the key is too far off from perpendicular, the distortion of the non-linear will prevent an accurate identification of the key blank.
In light of the foregoing, there is a need for an improved key identification system that (1) has a reduced number of moving parts; (2) is easy to use; and (3) has improved accuracy and speed of key identification.